Comparative study: The effects of solvent on the morphology, optical and structural features of regioregular poly(3-hexylthiophene):fullerene thin films

In this report the effect of solvent to control the degree of mixing of the polymer and fullerene components, as well as the domain size and charge transport properties of the blends were investigated in detail using P3HT:C60 films. The polymer blend films spin coated from faster evaporating, non-aromatic solvents demonstrated an improved ordering and optical absorption in P3HT and blended films, indicating that the limited solubility of P3HT:C60 in a marginal solvent can lead directly to optimal morphologies on the films. The PL quenched by a factor of 3 after blending the P3HT with C60 in a 1:1 wt. ratio using CB, xylene, DCB, and toluene as solvents, indicating a partially charge transfer from P3HT to C60. A complete reduction in the PL intensity was observed in the film spin-coated from chloroform.